1. Field of the Invention
The present invention relates to a flat display device for executing AC plasma discharge display and a fabricating method thereof.
2. Description of the Related Art
As a flat display device utilizing plasma discharge, for example, Japanese Patent Application Laid-Open No. 7-220641 (1995) discloses a display device.
As shown in a schematic exploded view of a main portion in FIG. 7, for example, in the example of the conventional flat display device, first and second substrates 101 and 102 which are made of glass substrates oppose each other with a predetermined interval and surroundings of the substrates are sealed airtightly so that a flat container is constituted.
A discharge maintaining electrode group 105, which is composed by arranging plural pairs of discharge maintaining electrodes 103 and 104 which are made of transparent electroconductive layer, for example, in parallel, is formed on an inner surface of the first substrate 101.
Partition walls 106 which are extended to a direction intersecting perpendicularly to an extended direction of the discharge maintaining electrodes are disposed in parallel at predetermined spacing, and address electrodes 107 are formed between the partition walls 106 in a stripe form, and fluorescent materials R, G and B, which emit lights of red, green and blue, for example, due to excitation by means of ultraviolet rays generated by plasma discharge, are applied between the partition walls 106 on an inner surface of the second substrate 102.
A necessary discharge starting voltage is applied between the selected address electrode 107 and one discharge maintaining electrode so that discharge is started in a portion where they cross each other, and a necessary AC voltage is applied between the paired discharge maintaining electrodes so that the discharge in this portion is maintained, and the fluorescent material positioned in the crossing portion is illuminated by an ultraviolet ray, for example, of an energy light emitted due to the discharge. In such a manner, luminous display is executed.
A conventional general plasma discharge type display device uses so-called negative glow discharge. The negative glow discharge takes place between electrodes which are disposed with spacing of 130 xcexcm to 200 xcexcm, for example.
Therefore, in this case, since the electrode gap, such as the gap between the paired discharge maintaining electrodes, cannot be enough small, a pixel pitch is naturally limited, and thus in the case of high-definition display, heightening of pixel density is hindered.
In the present invention, the high-definition and high-density display in the flat display device are improved, and a driving power, namely, power consumption is reduced.
Namely, in the present invention, in a flat display device, plasma discharge is allowed to take place by mainly utilizing cathode glow discharge.
A flat display device of the present invention is constituted so that first and second substrates are disposed so as to oppose each other, and a discharge maintaining electrode group which is constituted so that a plurality of discharge maintaining electrodes are disposed is formed on the first substrate, and an address electrode group which is constituted so that a plurality of address electrodes are disposed is formed on the second substrate, and particularly plasma discharge display is executed by cathode glow discharge.
In addition, a method of fabricating a flat display device according to the present invention includes:
the step of forming a discharge maintaining electrode group, which is constituted so that plural pairs of discharge maintaining electrodes are disposed with their mainly extending direction defined as a first direction along a surface of a first substrate, on the first substrate; the step of forming grid-state projecting bars which are constituted by projecting bar portions, which are extended to a direction crossing the discharge maintaining electrodes and disposed in parallel at necessary spacing, and intersecting projecting bar portions, which cross the projecting bar portions and are extended along between a pair of the discharge maintaining electrodes;.the step of forming a projecting wall group, which is constituted so that a plurality of projecting walls extending to a second direction along a surface of the second substrate are disposed in parallel, on the second substrate; the step of flying an electroconductive material onto the projecting walls from diagonally above a direction crossing the second direction and cladding the electroconductive material selectively to top portions of the projecting walls and side walls in vicinities of the projecting walls so as to form address electrodes, which are constituted by the electroconductive material formed on the top portions of the necessary projecting walls, on the second substrate; and the step of applying a fluorescent layer between the projecting. walls, wherein the first and second substrates oppose each other so that their directions face towards directions where they cross each other, and the projecting walls and the intersecting projecting bar portions at least work together so that spacing between the address electrodes and the discharge maintaining electrodes is set to a predetermined spacing.
According to the flat display device of the present invention, at least in the discharge maintaining, the cathode glow discharge can be allowed to take place, namely, the spacing between pairs of discharge maintaining electrodes can be set to be narrow, namely to less than 50 xcexcm, i.e., not more than 20 xcexcm. As a result, a pixel pitch can be reduced, and high-definition and high-density display can be executed.
In addition, in the present invention, since the cathode glow discharge takes place, a driving electric power can be reduced further than the case of a negative glow discharge, and an electricity-saving effect particularly in a large-screen display is improved. Namely, what the present invention refers to the cathode glow discharge is, as is clear from the object and effect, mainly the one, but also includes the case that another discharge mode which is incidentally generated is mixed.
In addition, according to the fabricating method of the present invention, in the case where the spacing between the first and second substrates is defined by the projecting bars and projecting walls formed respectively on the first and second substrates, the electroconductive material is deposited on the top portions of the projecting walls so that the address electrodes are formed on at least predetermined projecting walls. However, since the electroconductive material is allowed to fly from the diagonal direction, the electroconductive material can be formed isolatedly on the top portions and in the neighborhood of the projecting walls, and accordingly the address electrodes can be separated from each other at the same time when they are at least formed. As a result, the address electrodes can be easily disposed densely.